A switch (SW) for detecting the operation of the brake is usually installed in the vicinity of the brake pedal in a motor vehicle, so that when the brake pedal is stepped on by the driver, the SW may be energized (or de-energized) to turn on the brake lights.
It has hitherto been the case that the brake lights are turned on or off in response to the operation of the brake (ON) or its release (OFF) by the driver.
Measures other than the ordinary brake lights have been proposed to prevent the collision of a vehicle with a vehicle, etc. ahead from behind. For example, JP-A-2002-6035 discloses a system including a radar apparatus mounted on a motor vehicle for determining the distance between two vehicles and the relative speed thereof as required to give a warning or have the brake operated automatically on behalf of the driver when the vehicle has come too close to the vehicle ahead.
The prediction of possibility of any collision based on outside pictures taken by a radar or onboard camera is very expensive because of the radar or camera and control devices therefor which it requires. The brake lights presently available reflect only the presence or absence (ON/OFF) of brake operation and do not reflect at all the effects exerted by brake operation on the vehicle or its surroundings, or the importance thereof.